Length-weight and length-length relationships, sex ratio and condition factors of the Asian striped dwarf catfish Mystus tengara (Hamilton, 1822) (Siluriformes: Bagridae) in the Ganges River, Northwestern Bangladesh

Abstract

The present study describes the sex ratio (SR), distribution of length-frequency (DLF), relationship of length-weight (RLW), relationship of length-length (RLL) and condition factors of Mystus tengara , a small indigenous freshwater fish species. A total of 881 specimens ranging from 4.3-11.4 cm L T (total length) and 3.8-9.6 g WB (body weight) were investigated in the Ganges River of Rajshahi, northwestern Bangladesh from January 2010 to December 2010. The overall sex ratio showed significant differences from the expected value of 1:1 (df=1, χ2=8.9, P 0.91, distribution of length-frequency). The value of Fulton’s condition factor (KF) was ranged from 0.9 to 1.2 for male and 1.0 to 1.5 for female M. tengara . Also, relative weight (WR) was significantly higher in females (WR>100) than in males (WR<100) indicating imbalance habitat with food availability.